The rally is the latest demonstration since a recent decision to resume using nuclear power in Japan following a total shutdown.

It is believed at least 10,000 demonstrators have taken part in the early stages of the march. They will form a human chain around the parliament in the evening.

"After the Fukushima disaster, I thought that the government and vested interests were telling us lies about nuclear power being safe," said Miho Igarashi, 46, an architect from Ibaraki prefecture south of Fukushima.

The rally is the latest in a string of protests in Japan, which has seen a rising tide of anti-nuclear sentiment since Prime Minister Yoshihiko Noda in June ordered the restart of two reactors.

Mr Noda has defended the move citing looming power shortages after Japan switched off its 50 nuclear reactors - which provided the resource-poor country with a third of its energy - in the wake of the Fukushima disaster.

Weekly demonstrations outside the prime minister's residence have drawn tens of thousands of people and a rally in west Tokyo earlier this month saw a crowd that organisers claimed was about 170,000-strong.

Sunday's protest took place in high temperatures under a blazing sun, and the crowd included families with small children.

"I decided to join the protest because nuclear reactors are resuming even though their safety is not guaranteed," said Sayaka Suzuki, 28, who was with her three-year-old daughter.

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